Why mp3s suck, and how to hear it

DO NOT read this post if you have a large collection of mp3s, enjoy listening to them and can’t hear any problems with them, because it’ll ruin them for you !

There’s been plenty written on how mp3 works, and why lossy compression sounds worse than uncompressed audio in general. My aim here is to demonstrate how mp3 sounds bad, for all the people who keep telling me there’s no difference.

I’m going to give you clear guidelines and examples on what to listen for and the negative effects of mp3, but there’s no going back – once you can hear the problems, you’ll never stop hearing them.

This isn’t limited to audiophiles, or “golden ears”, by the way – in my opinion anyone can hear this stuff, with a few pointers.

First, I need to make this clear – I have nothing against lossy audio or data compression in itself – I do most of my casual listening on an iPod, using 128kbps AAC files – they sound fine. Not as good as the original CDs, obviously, but OK. And yes, I’m well aware that AAC is just a more advanced version of mp3. But the fact is that mp3 has fundamental limitations – even at higher bitrates.

Next – I’m also a pragmatist. mp3 is a temporary phenomenon, just like AM radio, cassettes and CDs. In the long run, none of those have killed music, and neither will mp3, or lossy compression in general. So, why the rant ?

Because people keep saying mp3 sounds great, or “indistinguishable from CD” and it’s just not true.

mp3 isn’t good enough

It doesn’t matter what encoder you use, it doesn’t matter what settings you use or what pre-processing you apply – mp3 just doesn’t cut it. AAC and later, more sophisticated encoders use more advanced encoding methods, and sound better to varying degrees, but mp3 just FAILs.

How does it fail ? That depends a little on the encoder being used, but some of my own pet hates include:

mp3 sizzle – the artificial, unnatural swirling metallic noises that sound like someone’s added chime bars to everything, or there’s a mosquito buzzing in your ear. Some people actually say we prefer these noises in mp3s – but the research says bullshizzle !

Added distortion – Yet another side effect of the so-called Loudness Wars. mp3 encoders rarely include any headroom for the encoding process itself, so the added processing pushes the music even further over the limits, generating inter-sample peaks and adding even more distortion in the process

Flat, two-dimensional sound mp3 works by throwing away musical information that we supposedly can’t hear – up to 90% of the original information, at 128kbps. That means all the subtle, delicate stuff, like ambience, space and realism. So a lush, three-dimension original is reduced to a flat, cardboard replica of itself

Mushiness All but the very best mp3 encodes just sound fuzzy, muddled and – well, mushy !

Hear for yourself

Don’t take my word for it – here are some examples. First, a truly nasty 128kbps mp3 example, from a Deep Purple live album I mixed a while back:

3TalkAboutLoveAmLow

(Before anyone jumps on me, I’ve heard even a 256 kbps mp3s sounding like this – I’ve just used a low quality version to make the point.)

If that doesn’t sound too bad to you at first, try this – I’ve filtered the file to highlight the high frequencies. You can hear the problems most clearly when the vocals start:

swirlies

Some people describe this effect as “sizzle”, or “swirlies”. It’s not just that I’ve removed all the bass, what I’m pointing out is the unatural bubbling, twinkling “chime-bar” type sound, or as my friend and fellow mastering engineer Nick Watson once called it, the “flocks of tweeting ultrasonic birdies”. It also reminds me of someone crinkling up tin foil !

Once you’ve picked it out, listen the first version again. Doesn’t sound so nice now, does it ? Can you ignore the swirlies, now you know they are there ?

Now listen to the original file:

3TalkAboutLove

Listen to the clarity, punch, and bite of the WAV, compared to the swirly, soggy mess of an mp3. Which one do you prefer ?

The loss of depth, richness and three-dimensionality is more subtle side-effect, but just as unfortunate. Here’s a snippet of a recording I did for the brilliant Hans Koller, featuring Christine Tobin on vocals:

GreatBearTheSmall

(This is a much better mp3 encode, with far fewer heinous swirlies. But still…)

Here’s the WAV version:

GreatBearTheSmall

Don’t expect the difference here to leap out at you straight away, it’s more a case of feeling it – listen to the swirls of the harp from 30 seconds in, listen to the piano and Christine’s voice – on the wav file, there’s a warmth, and a depth, and a sparkle that in the mp3 has just gone.

Listen to the wav several times over, then switch to the mp3. Do you honestly feel it sounds as good ? The mp3 is OK, but it’s just… meh. I’m not drawn in, my attention wanders, it doesn’t move me.

Something essential has been lost, and you can’t get it back. And once you’ve heard that loss, even cranking the data-rate up doesn’t help. The only solution is a more advanced format, or lossless files.

Try listening to the mp3s in your music collection. Go back and compare them to the CDs you ripped them from.

…Sorry.

Update:

I’ve had lots of interest in this post, and lots of discussion, especially on link-sharing sites. There are a few common responses that I want to answer here.

No-one uses 128 kbps mp3s

Wrong. If you’ve made this comment, you probably already know about LAME and the all other flavours of mp3 codec, and you probably do choose to use higher bit-rates, but you’re in the minority. Most “regular listeners” go for the default settings – and even in iTunes this is only 160 kbps.

192/320 kbps sounds fine

Sometimes. This depends so heavily on the material, the encoder and the codec – you simply can’t make blanket assumptions. Ironically one of the factors that makes mp3 so popular – the fact that there are so many encoders and players, some of which are free – also makes it far harder to get a decent encode. By contrast, the grip Apple have over the AAC format at least ensures consistently high standards of encoding.

You’re just an Apple fanboy

No. Well alright, yes – I am a big fan of Apple’s products, but there are plenty of other alternatives to mp3 – OGG Vorbis, FLAC etc. The only reason I mention AAC a lot is it’s a format I have deep experience of, and always sounded good (but not perfect !) to me.

And another thing

To everyone who keeps saying “just use 320 kbps”, I say – why ?!? mp3 simply has inherent limitations compared to other formats. The whole point of lossy audio is to save space. At 128 kbps that saving is 90% – well worth having. At 320 kbps though, that saving is only 60% and it still doesn’t sound great – I’d far rather go with FLAC or Apple lossless, which can often achieve an almost equivalent 50% saving in space, and have something that sounds identical to the source.

Update #2 (2014):

Five years later, and the mp3 (and lossy data compression in general) is still with us.

Related posts:

Comments

Well iPod suggests portable listening and most people have lower demands for that than more “serious” forms of listening. It doesn’t have to be “true to the original” just “good enough to listen to”.

As for AAC it stays “good enough to listen to” for very low bitrates.

I think however that Ian’s problem with this isn’t what people listen privately to on their iPods or Sansas or whatever music player you use, it’s your choice what codec to encode with and at which bitrate. The problem is that music are being sold already encoded in MP3 formats which means that someone else already made the choice for you.

What I HATE about the MP3 format, is that starting during the `00s, and increasingly thus far throughout the “20-teens” era, Rock and Pop artists have “mixed” their music so as to still sound alright on the highly compressed and crappy MP3 format. ALL contemporary music these days just sounds “loud and blaring”; without anything akin to the dynamics and naunce that music USED to have, especially during the `70s, but also during the `80s, and 90s. Everyone, even Country and “soft Pop” artists, “mix” everything to sound LOUD. If a person plays such music at “normal” volume levels, it sound blaring; and if you play it at a lower level, it just sounds “dull”.
~ Personally, I can`t wait until the increasingly tiny and affordable “storage medium” revolution gives us iPod type devices with Gigabytes-worth of data storage space, so that common people can download large amounts of songs in WAV file, or Direct Stream Digital encoding format. THEN the artists can resume using dynamics in the recorded performances, like music SHOULD BE.(Anyone that may have any “inside information” on how or when this developement may be occuring, please do reply to this comment.)

Just to stir things up a bit. I am a musician with a home studio. I record music in wav format at 32 bits and 44100 Hz. I listen on studio monitors 1 meter away from my ears mounted on insulated stands in a room with sound absorption to reduce unwanted reflections. I spend hours finding exactly he sound I want.

But when I am not recording music I listen to my collection on mp3. I have ripped all my CDs to mp3 and chucked the originals. I carry a Creative Zen around with all my music on and I love it.

The important point here is how the mind and ears work together. I know all the records in my collection very well, I love them. So I don’t need perfect, or even very good, reproduction to enjoy them. I just need enough to remind me how they sound and the incredible instrument that is the brain fills in all the rest.

Sure I listen to new music in good quality, but once I know a song mp3 is plenty good enough for me!

Please kill me before AAC or ALAC become new mediums of sound. I prefer my music without blaring corporate watermarking from a terribly restrictive iTunes service, thank you very much.

But aside from that, I’ve shown these examples to a few friends in their mid thirties and fourties. All of them have been able to pick out these correctly, among other web-based tests, in a matter of four seconds with mid-range equipment. Even the MP3 – FLAC difference test is blaringly obvious to most of the people in question. I have no doubt that this is going to prove less successful with a younger crowd, even with their more dynamic reception of the frequency band.

For the Talk About Love example, the wav is also lacking in a rich sound stage and dynamic range — That’s much worse to me than the swirlies. I guess what I am challenging is — would better mixes come out more acceptably through the compression process, esp if they’re at >= 320 kbps?

More dynamic, open music often survives encoding better, because the encoder has to work “less hard”, and so has “more to work with”. However mp3 just don’t do as good a job as more advanced codecs – an AAC of that track can sound pretty good (and to be fair, you can get better mp3 encodes of it, too.)

Higher bit-rates almost always help, but really why bother, these days ?

I’m not aware of “swirly reduction” decoding, but such processing will always have further side-effects, like attempts to remove “mosquitos” from jpeg images, for example. At the end of the day, once the information is gone, it’s gone…

I agree that mp3 is not the best format for compressed music however it is the only format that I know that works in both itunes and windows media player. I need a format that allows me to play music on my smart phone and my ipod touch and my computer easily without having to hunt down third party plugins and other forms of manipulation.

Every mp3 has a tiny bit of silence at its beginning, resulting from the conversion process. Just listen to a live CD converted to mp3, you will always hear that gap on every track transition, which ruins the “live experience” for me if you know what I mean. People alway comlain that flac and the likes are inconvenient formats for their iPod/iPhones etc., in fact they just need a proper audio player software that supports the format, or get the right plugin or in the case of apple use apple lossless etc. most of the stuff is free and easily to find if you know how to make use of google.

I would like to know how many people actually tried an ABX test with a properly encoded LAME (V0) vs the original Wave. I’m talking about ABX because you’re listening without KNOWING if you’re listening to “A” or “B”.

There’s no excuse not to try this, and I’m sorry, but I can “distinctly” hear the difference between two power cords… …when I’m looking at it!

This is not to say that even a properly encoded mp3 isn’t going to lose sound quality to the original (it will always happen), but many of these artifacts are clearly outdated or present on lower bitrates/worse encoders (btw, I’m sorry, but using iTunes to encode mp3 is NOT the best option).

I never bought a single song on iTunes or another paid download service.

In 2013, I feel that it makes no sense in buying lossy compressed tracks anymore.
I’d rather buy the original CD (which I can then compress to my format of choice, be it lossy or lossless), which is somehow obvious if we consider that sometimes it isn’t more expensive.

But my format of choice is lossless music downloads like HDTracks and similar services.

Many of these recordings are better not only because of the greater definition of the format, but also because it is mastered with different goals in mind (compared to the CD version), and it usually has a lot more dynamics.

Take the latest album from Muse as an example, and you don’t even need to actually hear it. Load the 2 versions of same song in your fav audio editor and the greater dynamics are pretty clear.
It’s also a pointer to the fact that the CD version could also have (a lot) more dynamics.

The mp3/aac is all about portable sound. The same 16 GB iPod filled with music at ~200 kbps is going to hold a lot more music than if we use ALAC versions.

It’s debatable if most listening conditions on a mobile device will ever give real benefits between these two compression examples.
It’s very easy for the outside noise and earbuds quality to have a greater impact than the one given by a V0 LAME encoded mp3.

But I wouldn’t (and I don’t) use 128 kbps bitrates for pretty much anything, portable devices included.

And most importantly, iTunes is only going to see my money on music if they release lossless compressed tracks in the future.

Coming back to where I started, I strongly suggest an ABX test with the best versions of LAME mp3 encoding.
I won’t say that you’ll start loving mp3 sound, but it can definitely put things in perspective.

If one really wants to hear, one must close the eyes and other input devices besides the ear.

Personally I hope MP3 format just dies off within the next 5-10 years kind of like how it took a hell of a long time for the VHS format to die off. I have my personal music collection in Ogg Vorbis format using the latest version of the Xiph.org encoder from Feb 2012 and at the setting I use which is -Q9 I can honestly say in comparison to old MP3 tracks I had of same songs ten years ago the difference in quality with Vorbis is like a huge breath of fresh air. In short it blows MP3 out of the water.

It also doesn’t help that since 1991 when MP3 came out there has been a glut of horrible MP3 encoders over the years such as Xing and Qdesign didn’t help. LAME improved upon it and is still updated even in 2013 but it’s still has to follow the inherent limitations of the MP3 format.

In regards to Android phones I know with alternate music players on 2x and 3x firmware devices/tablets you can play Vorbis and flac files with no problems, 4x supports OGG in the default music player, and with iPhones/Ipods/ipads running iOS 4.3 or later you can use a music player called Capriccio that allows you to actively bypass iTunes to transfer over OGG Vorbis/flac files via Wifi or FTP transfers to the device.

I have an old friend who loves music, classical and popular and he downloads vast amounts of stuff from the www. I say to him “If you love music why would you subject yourself to such bad sound quality , bereft of humanity , dynamics, detail and musicality?” He knows I am an audiophile vinyl nut but regardless, how is it that a whole generation of people don’t even own a cd or record player and some decent speakers and think playing music through their mobile phones via tiny ‘ear buds’ is satisfactory? . I think it is quality versus quantity.
It is his / their loss. Music sounded better when it was recorded on audio tape and pressed onto vinyl . The digital remasters I am hearing of Van Morrison( Into the music ), The Beatles( the shite album), Brahms( clarinet quintet), The Band ( The Band ) and so on have all been ‘brickwalled’ and do not sound anything like the true original recordings.I can’t dig remastered recordings at all
MP3 ‘s are even worse! .

Again, blind test between 256 kbps VBR MP3 and CD-quality lossless and I can pretty much guarantee you won’t hear a difference between the two. You can’t say it’s worse if you can’t hear the difference.

“…so on have all been ‘brickwalled’ and do not sound anything like the true original recordings”
Often times the digital remasters of albums are terrible and are affected by the “loudness war” effect. A lot of them do indeed sound just plain bad.

128kbs aac sounds garbage through a hifi, it’s not subtle. 320kbs lame (slow-high setting) mp3 however sounds close to a CD and certainly better than the 256kbs aac crap that iTunes sells (played through a hifi) and yes I’ve done blind tests. The sound from aac doesn’t do it for me. 320kbs ogg sounds better than lame though.

I can’t tell a difference between MP3 or AAC or Ogg Vorbis or Opus at high bitrates.

I can’t remember what bitrate I used when I tested, but I think it was 48 or 56 kbps. MP3 was as bad as expected, lacking any high end. HE-AAC was generally good except for drum hits which had an annoying “sucking” sound. Ogg and Opus was very good, although still discernible from the original.

I love Classical music and Opera where you find more than a hundred musicians (and singers) playing at a time,.. so, you need detail clarity and a good sound space.
Loosles encoders are the thing,….(“more if you pretend hearing your music at your place,”)
…. WAV is great but far too big in size, so the second best option for me has been FLAC,,….so you can record on WAV and then make the change to FLAC,….the “VLC” (free)audio programm is great and supports FLAC.

My friend, first of all you don’t even know the basics on how digital music is analogized by a sound card, you didn’t even specify what sound card are you using to make those assumptions not to mention the 2nd dimension of a digital file which is the “bit depth” If your sound card is set to 16bit you cannot hear even wav files at the most top quality. Listening an audio CD will bypass the DAC conversion and will output the highest quality. Ihave all my mp3s encoded at 320kbps with 24 bit depth and I can hear the sharpest bird chip. First of all by a dedicated sound card that suppoer 24 or 32 bit dip output and rewrite this article

I tried my own blind test, not really trusting the sound quality of web browser plug-ins. I took the WAV of “The Great Bear and the Small” above and made my own mp3 using lame 3.99 with the –medium preset, producing a VBR MP3 averaging 145kbps.
I made a playlist of several copies of the WAV and the MP3 in my music player, put it on random order and listened to the track closely on headphones, over and over again. I could not discern any difference, and my guesses as to which it was were wrong as often as right.

I saw all comments regarding the quality of the sound in any format, First of ALL you have to have passion for a Good quality music listing and you love crystal clear music here are some points in my experience listing music for years.

1:- Vinyl are the best using Shure or any good quality cartridge.
2:- Cassette are next but not too many people listen anymore.
3:- Wav format is current.

Things to Remember in any music
Noise Level
Hissing in a Song
Loudness Level
Normalize Level

If your Master is badly recorded or remastered or have too much loudness which kills the dynamic of a song you cannot do anything by converting to Flac or mp3 or any other format unless you remaster and bring the life back in the music, i always remaster music with Wave lab & Adobe Audition which brings life back to the music and then you bring it to ANY format sounds amazing, feel free to send any comments or feedback or any demo of mp3 file i will be glad to send you a sample of it so you know what you missing.
Thanks

Yes, you can test yourself, cassettes have Magnetic Coating which increases the dynamic range and Frequency response,if you get Metal,Cro2,Fe-Cro2 Tapes but do not record them more then “0” Zero db at any cost best is to keep under zero db ie -0.3db, if you have High Quality cassettes Deck with Bios adjustment outside with 3 heads so you can Monitor your Recording for highest quality recordings, i have still some old cassettes which were recorded Years back on Pioneer cassette Deck CT-F950 from the album’s they still sound better then nowadays Cd’s or mp3, mp3 is lowest format which strip out your highs,Mids,and bass sound, Life is short Enjoy the best of the best ….

It is all so simple – just use apple losless for itunes, or flac for other players. Itunes can do 24/96, and even and iPhone can do 24/48. This is WAY better than CD sound! Just get your favourite music on DVD-A (it comes as 24/96 typically), or SACD (these are tricky to rip, but not impossible), and you will never want to listen to mp3 or poor quaity digital radio again. You may even not want to listen to CDs afterwards – you have been warned. You will understand what real sound of music is.

There is a small number of stations on the internet broadcasting loseless formats. Support them!

@ Gabriel – I just followed your link and unfortunately the trial isn’t really valid. To do this kind of comparison you need to be able to ABX – ie. compare the “mystery” clip with something known – and you need to be able to do it seamlessly.

@ Ian Shepherd – Thank you for having a look at my test, Ian. Of course the ideal situation is the one you describe, which is out of my reach to be offered online. What you saw is the closest to the ideal I can get if my main purpose is to be able to gather data online using unsofisticated tools. Giving people the chance to do the ABX testing on their own would yield pretty unreliable data. Anyway, what I am trying to prove with my blind test is that differences are not “night and day” as so many people claim. In fact, they are very, very subtle. So much so that almost everybody fails to detect them. Of more than 300 records I have been able to gather, only to people have proven they can tell AAC 256 and lossless apart with sufficient statistical confidence… using excellent audio gear for their trials. I was hoping you would be the third, for what I read in your article….

@Gabriel – With the amount of test results you claimed to have gathered, it is completely possible that the two people who aced your test were able to randomly guess them all correctly (a very slim chance, mind you) or found a way to cheat it.

It’s actually pretty funny, all the folks who assert that no audible difference exists between mp3’s and other uncompressed formats because they were unable to hear it. Of course it depends on the listener, both physiologically, and neurologically, and on the complete audio chain. Even with relatively low distortion components in the audio chain, I would suggest that still, the average listener will not notice a difference. More significant, the vast majority of people who listen to music in the mp3 format probably don’t care! For those who are interested though, I will give a hint: Even if you don’t have extensive ear training, you will probably have a better chance at discerning the difference if you listen in stereo with headphones, and if the recorded material has either a stereo acoustic field recorded by a binaural or stereo microphone pair, or if the recorded material features a prominent stereo effect, say for example, a nice rich stereo reverb algorithm. Percussive sounds also serve to make the difference between digitally compressed and uncompressed files easier to hear. The main thing I would say is that it’s much easier to hear distortions with a very high fidelity component audio chain, and if the program material you are listening to has prominent stereo information. If you can’t hear the difference, then you are lucky! You will probably enjoy the music more! 🙂

P.S. I did extensive testing many years ago and found that AAC was a much more transparent format, with FLAC beating both AAC and mp3 hands down. Uncompressed formats were the best. Even with uncompressed formats however, if you have a good ear (and young ears) and your audio chain is good, you can even hear the difference between sampling rate and bit depth settings with uncompressed file formats like WAV, though the differences are more subtle. At least for me, and with my set up, the threshold was that any combination of sampling rate and bit depth above 48k/16bit or 44.1k/24bit offered such little improvement that I didn’t feel it was all that necessary. No doubt others have had different experiences. I think that most of the time, there will exist sufficient ambient noise masking in listening environments that this kind of hair splitting doesn’t matter. 😛

Another note: Up until recently, I found that the analog performances in most audio chains introduced enough distortion that it was difficulat for me to hear the difference between 48k/24bit and higher sampling rates up to 96k for example. Distortion figures tend to be all over the place for consumer and even some professional audio gear, as some engineers just don’t get it and use crappy components, or the engineers deliberately pick a component for its characteristic “musical” distortion (e.g. in a mic or instrument preamp or EQ), or the accountants get into the act and they are forced to use inferior spec parts to increase profit margin. So the analog chain, what chips a media player uses for example, can make a big difference! As stated in my previous post, differences in distortion are much more pronounced in relation to stereo program material.

To all these who say there is no difference between unompressed 24/48 or more, and 320kbps – just listen to a good, new recording of classical music, with lots of violins, cellos, percussions, trumpets, etc. It is indeed hard to hear the difference if you listen to pop music, but equally it is hard to listen to classical music in lossy formats, it just does not sound right. FM radio was more pleasan to the ear; it did not have the frequency range nor the dynamics, however the power spectrum was more realistic. To me, cello, guitar or good voice all sound in mp3 like outline without fill.

I’ve always been skeptical of people saying they hear a (huge) difference between even the highest quality recorded MP3’s and lossless. There are so many myths in the audio world that I generally take every audiophile statement with a big bag of salt at first. It’s nice to see some evidence from a trusty source for once, because everyone I ever subjected to a blind test (and I would never bother with 128kbps, it’s not 1999 anymore, so it’s at least “preset-standard”) failed it. I’m usually pickier than the average person, but even if I hear it, it doesn’t really bother me.

My point is basically that this seems to be a 1% vs 99% situation. Even if a small and picky group of people can both hear it *and* are also annoyed by it, is that then a good enough reason to subject the whole world to big lossless files and a need for so much more storage just to avoid a few tjirps? I think that’s a lot to ask.

A very good method to reveal what mp3 does to the audio signal is to listen to the side information. If you have a VST compatible DAW or mastering software, open an mp3 with it and load an M/S tool into the mix- or masterbus, which let’s you listen to the mid/side information. (for instance the bx_solo from Brainworx, good Freeware tool!) Listen to the side signal and everyone will hear those artefacts, that occur even in mp3s with 320kbps of quality.

Also, I think it’s more like a 10% 90% split – and that’s for people who know they can hear a difference. I think many others register these effects subconsciously, and it just eats away at our enjoyment of music.